There's a lot of common wisdom around building good habits: stick to a schedule, reject constraints, and seek out great advice. But science would like a word. Katy Milkman is an economist and behavioral scientist who has done breakthrough research on how people form (or break) habits. Surprising data from her book, How to Change, shows that flexibility, not routine, is the key to conquering procrastination, exercise, and more. Environmental changes, even small ones like the start of a new week or a new year (resolutions, anyone?) can be psychologically huge in effecting change. And constraints on creativity often yield better results than unlimited resources. Science also explains why when it comes to mastering a skill, tis often better to give advice than to receive it.